Mark Twain, born Samuel Langhorne Clemens, was a renowned American author and humorist known for his witty storytelling and keen observations of human nature. His most famous works include The Adventures of Tom Sawyer and Adventures of Huckleberry Finn, which explore themes of childhood, race, and morality in America during the 19th century. Twain's writing style combined humor with social criticism, making him a significant figure in American literature. He often drew from his own experiences growing up along the Mississippi River, which greatly influenced his narratives and characters, leaving a lasting legacy in the literary world.